1. Field of the Invention
This invention relates to bending wires and, more particularly, to a method and apparatus for bending selected, individual, electrical wires at the stripped end of a ribbon cable.
2. Description of the Prior Art
The development of new electrical cables in which a large number of wires are encapsulated in a flat insulating web has produced significant advantages in computers, telecommunication devices and the electronic industry generally. These cables are presently manufactured with conductors formed as fine parallel wires, as small as 0.030 inches in diameter, located on closely spaced centerlines. They may be used for transmitting either electrical power or electrical signals.
Along with the obvious advantages of size reduction and ease of handling, such flat cables also present certain disadvantages, both mechanical and electrical. From the mechanical standpoint, the fineness of the wires and the closeness of their spacing generally increase wire handling difficulties during the coupling of the individual wires to other electrical components such as connectors. Further, since their centerline spacings are unusually small, they may not necessarily coincide with the standard centerline spacings for commonly used electrical elements. This creates interconnection problems. The development of even smaller cables with finer, more closely spaced wires, further aggravates these mechanical problems. This, in turn, complicates both the design of connectors compatible with such further miniaturized cables as well as the interconnection of such cables to their connectors.
From the electrical standpoint, particularly when flat cables are used for signal transmission purposes, the closeness of wire centerlines dictates their positioning at a specific, precise, constant distance for a particular application if the accurate transmission of signals is to be accomplished. Of equal importance, when flat, multi-wire cables are coupled with connectors, such connectors must be designed for controlling the characteristic impedance of the transmitted signals while matching it to the ribbon cable as well as the electronic devices being coupled.
The prior art discloses many techniques for coupling ribbon cables to connectors. Note, for example, U.S. Pat. Nos. 4,094,566 to Dole et al; 4,181,384 also to Dole et al; and 4,367,909 to Shatto et al. None, however, discloses a method or apparatus for efficiently bending or deploying selected wires of a ribbon cable in order to facilitate the coupling of the ribbon cable wires to connectors as herein disclosed. Further, no prior art discloses a method or apparatus capable of bending selected, individual, electrical wires at the stripped end of a ribbon cable wherein such wires are as small as 0.008 inches in diameter as contemplated by the present invention. This is several times smaller than wires previously employed. Such significantly reduced wire diameters will allow for the proportionate reduction in the spacing between centerlines to 0.0125 inches along with a proportionate increase in the number of wires per ribbon cable to 81 wires per linear inch.
While U.S. Pat. No. 4,616,893 discloses a connector with controlled characteristic impedance between printed circuit boards, an environment in which the present invention finds particularility, there is no prior art teaching or suggestion of wire bending for flat, multi-wire, signal transmission cables. In addition, U.S. patent application Ser. No. 937,737 filed Dec. 4, 1986, in the name of Siwinski and commonly assigned to the assignee of the present application, discloses a connector with appropriately bent or deployed ribbon cable wires for coupling with a connector as disclosed herein. Such application, however, does not teach, disclose or even suggest any method or apparatus for conveniently and accurately bending such wires to facilitate their coupling.
Lastly, U.S. patent application Ser. No. 661,774 filed Oct. 17, 1984 in the name of Schwalm discloses the soldering of closely spaced bent wires as of a ribbon cable to connectors. Such disclosure, however, does not teach or suggest any method or apparatus for bending ribbon cable wires for use in association with connectors, let alone the inventive method and apparatus as contemplated herein.
None of these prior art patents teaches or suggests the accurate, efficient, convenient, and economical wire bending apparatus or method as described herein. Known methods and apparatus are simply lacking in one regard or another.
As illustrated by the prior patents, efforts are continuously being made in an attempt to more efficiently connect electrical elements of ever decreasing size. None of these prior art efforts, however, suggests the present inventive combination of method steps and component elements arranged and configured for bending the fine, closely spaced wires at the stripped end of a ribbon cable as disclosed and claimed herein. Prior methods and apparatus do not provide the benefits attendant with the present invention. The present invention achieves its purposes, objectives and advantages over the prior art methods and devices through a new, useful and unobvious combination of method steps and component elements, through the use of a minimum number of functioning parts, at a reduction in cost to manufacture and operate, and through the utilization of only readily available materials and conventional components.
These objects and advantages should be construed as merely illustrative of some of the more prominent features and applications of the present invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or by modifying the invention within the scope of the disclosure. Accordingly, other objects and advantages as well as a fuller understanding of the invention may be had by referring to the summary and detailed description of the preferred embodiment of the invention in addition to the scope of the invention as defined by the claims taken in conjunction with the accompanying drawings.